Alkylation



July 28, 1 959 A." K. ROEBUCK ET AL 2,

ALKYLA'I'ION Filed June 6, 1956 2 Sheets-Sheet 2 N Qli km mwm vlby E" m M V m M C 7 m A mm United States harem ALKYLATION Alan K. Roebuck, Dyer, Ind., and Bernard L. Evering,

Chicago, 11]., assignors to Standard Oil Company, Chicago, 11]., a corporation of Indiana Application June 6, 1956, Serial No. 589,674

6 Claims. (Cl. 260.-683.53)

This invention relates to catalytic alkylation and is particularly concerned with improvements in the alkylation of isobutane with olefins in the presence of an aluminum chloride-ether catalyst.

High octane number blending stocks for motor fuel have been made by the alkylation of isobutane With olefins such as propenes and butenes. using a variety of catalysts. The most widely used commercial process employs concentrated sulfuric acid as a catalyst. While the sulfuric acid alkylation process produces good yields of gasoline boiling range alkylate, it has certain disadvantages. A primary disability of the conventional sulfuric acid alkylation process is that the alkylate produced generally has an octane number of 90 to 95 CFRR, and the use of present and futtue high compression engines requires a gasoline having an octane number of 100 CPR-R or higher. In addition, there are certain inherent process disadvantages such as the necessity for using large amounts of acid (hydrocarbon/ acid volumetric ratios of' about 1:1 are employed) which requires the use of large reactors and makes for high operating costs of mixing hydrocarbons and acid. The low temperature used requires large refrigeration facilities. Although other al kylation catalysts have been developed, they are generally not capable of producing an alkylate having an octane number higher than that produced in sulfuric acid alkylation, and they frequently have other disadvantages such as poor yields, poor product distribution, etc.

An object ofthis invention is to provide an improved process for alkylating isobutane with olefins which produces good yields of gasoline boiling range alkylate having a high octane ntunber. an alkylation process requiring minimized refrigeration and which employs high ratios of hydrocarbon to catalyst and thereby minimizes the size of the alkylation reactors needed and reduces the operating costs of mixing the reactants with the catalyst. A further object is to provide an economical, simple, and efiicient process for alkylating isobutane with certain olefins to produce an alkylate having a higher octane number than is produced in commercially available processes such as sulfuric acid alkylation process.

When isobutane is alkylated with olefins in the presence of an aluminum chloride-ether catalyst, high yields (even higher than in sulfuric acid alkylation) of gasoline boiling range alkylate are produced. This alkylate, however, has an octane number which is undesirably low. To our surprise, we have found that when isobutane is reacted with certain olefins, namely propene, butene-2, and isobutene, using an aluminum chloride-ether catalyst under alkylation reaction conditions, that the octane number of the alkylate can be increased by as much as ten units by maintaining within the reaction zone between .001 and 1.5 weight percent (based upon isobutane and olefin present in the reaction zone) of a mononuclear aromatic hydrocarbon. This valuable improvement in octane number is obtained only when employing the named olefins.

Another object is to provide ice Likewise it is obtained only when employing the named catalyst which is a solution of more than one but less than two mols of AlCl in one mol of dimethyl ether and/or diethyl ether. No improvement in octane number is obtained when using olefins such as ethene or butene-1; and similarly, there is no substantial improvement in octane number when using other alkylation catalysts such as BF -ether-HF, BF -H O-HF, or concentrated H The aromatic hydrocarbon must be a mono-nuclear aromatic; for if a poly-nuclear aromatic is employed the catalyst becomes degraded rapidly. A polyalkylbenzene, such as Xylene or a hexaalkylbenzene is preferably employed, and preferably in an amount between about 0.1 and 1.0 weight-percent based upon the isobutane and olefin present in the reaction zone. The mono-nuclear aromatic hydrocarbon is preferably introduced into the reaction zone along with the isobutane and/or olefin.

As has been stated, the improvement in octane number of the product alkylate attained by use of this invention occurs only when alkylating isobutane with propene, butene-2, or isobutene. When the monofnuclear aromatic isv introduced into a reaction zone wherein isobutane is being alkylated with ethene in the presence of an aluminum chloride-ether catalyst, it stops the alkylation reaction. When the mono-nuclear aromatic is introduced into a reaction zone wherein isobutane is being alkylated with butene-l in the presence of the aluminum-chlorideether catalyst, the product alkylate has approximately the same octane number as is obtained when no mononuclear aromatic is introduced into the reaction zone. It is highly peculiar that when the olefin employed is propene, butene-2,, or isobutene, the octane number of the gasoline boiling range alkylate produced is increased by as much as 10 octane numbers. For example when butene-2 is employed, the octane number of the alkylate is increased from 89 CPR-R to 99 CFRR by the expedient of introducing approximately 1% m-Xylene (based upon isobutane and butenee2) into the reaction zone. Various refinery gas streams may be used as a source of isobutane and olefins in practicing our invention. For instance, the mixed butanes-butenes stream from catalytic cracking, together with additional isobutane, is a satisfactory hydrocarbon feed stock. The butanes-butenes efiluent from a butene polymerization process may also, be used, together with additional isobutane if needed, as a satisfactory feed stock.

The isobutane and olefin should be introduced into the reaction zone using an isobutane/ olefin Weight ratio of 3:1 or higher in order to obtain high yields of gasoline boiling range alkylate. While the octane number of the alkylate produced generally remains constant regardless of the isobutane/olefin ratio, the yield varies considerably with this ratio. It increases sharply as this ratio is increased and tends to level off after reaching an isobutane/olefin weight ratio of 3:1. Generally this ex,- ternal ratio (isobutane/ olefin ratio) may be between about 3:1 and about 10:1, e.g. 3:1 to 5:1.

The catalyst employed in this invention is an aluminum chloride-ether catalyst which contains more than 1 but less than 2 mols of aluminum chloride per mol of ether. In preparing this catalyst, dimethylether and/or diethylether is used. Catalysts prepared from higher molecular Weight ethers such as diisopropylether and higher are much too soluble in the reacting hydrocarbons to be useful. It is preferred to use dimethylether since the re sultant catalyst is less soluble in the hydrocarbon phase and therefore the catalyst losses are reduced greatly.

The catalyst is, prepared by dissolving aluminum chloride (anhydrous) in the ether. An aluminum chlorideether complex (which has an equimolar ratio 'of aluminum chloride and ether) settles out as the aluminum.

chloride is added. Heat evolved in forming the complex is removed to avoid evaporating the ether. After approximately one mol of aluminum chloride per mol of ether is added, the entire mixture becomes solid. The complex is melted by heating it to about 60 F. and additional aluminum chloride is added to the liquid complex. This additional amount of aluminum chloride is less than 1 mol of aluminum chloride per mol of ether in the complex, and therefore the finished catalyst contains more than 1 but less than 2 mols of aluminum chloride per mol of ether. To insure a saturated solution of aluminum chloride in the complex, the mixture may then be further heated, e.g. to a temperature of about 100 to 150 F., and subsequently cooled to about 75 F. for use. It is preferred to employ a solution which is completely saturated With respect to aluminum chloride, and a slight amount of solid aluminum chloride (as a slurry) might advantageously be present in the aluminum chloride-ether catalyst in order to insure complete saturation. Preferably the catalyst contains about 1.4 mols of aluminum chloride per mol of ether or thereabouts, which would correspond to approximately 80 weight percent algminum chloride and 20 weight percent of dimethylet er.

- The isobutane and olefin are reacted in the presence of the aluminum chloride-ether catalyst under alkylation reaction conditions such as are known in the prior art. These conditions comprise a pressure suflicient to maintain the hydrocarbons liquid in the reaction zone, a temperature at which the catalyst is liquid but below about 150 F., a hydrocarbon/acid volumetric ratio of from about :1 to 100:1; an external isobutane/olefin weight ratio of at least 3:1; an internal isobutane/ olefin ratio of 50:1 to 100021; and a contacting time of from 1 minute to 2 hours. The temperature in the alkylation zone should preferably be as low as possible while still maintaining the catalyst liquid, for the higher is the alkylation temperature the lower is the octane number. The alkylation process is preferably carried out at 50 to 100 F. The hydrocarbon/acid volumetric ratio is preferably between about 50 and 75:1. As this ratio is increased within the range of 10 to 100:1, the octane number of the alkylate is increased but the yield diminishes. Conversely, at the low ratios of hydrocarbon to acid the octane number of the alkylate is lower but the yield is greater.

As was stated previously, the aromatic hydrocarbon introduced into the alkylation zone must be'a mononuclear aromatic. The polynuclear aromatics appear to condense with themselves and form even higher polycyclic aromatics of an asphatic nature. The aromatic hydrocarbon is preferably a polyalkyl mono-nuclear aromatic. In general, the greater the number of alkyl substituents (which preferably have 1 to 6 carbon atoms in the side chain) the more elfective is the aromatic hydrocarbon in increasing the octane number of the allcylate produced, i.e., the more alkyl side chains in the aromatic hydrocarbon, the less is the amount thereof which is needed to cause an improvement in octane number of the product. Examples of various aromatic hydrocarbons which may be used are those such as benzene, toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, pentamethylbenzenes, hexamethylbenzenes, ethylbenzene, diethylbenzene, triethylbenzene, tetraethylbenzene, hexa ethylbenzene, isopropylbenzene, diisopropylbenzene, triisopropylbenzene, butylbenzene, dibutylbenzene, tributylbenzene, butylxylenes, mixtures of the above mentioned hydrocarbons such as might be obtained by extracting a hydroformate fraction with a selective solvent, etc. The aromatic hydrocarbon which is used may be recovered by distillation from the alkylate produced and recycled to the alkylation zone. Although it becomes alkylated, it nevertheless functions in the same manner in improving 4 7 tion zone in an amount such that between about .001 and 1.5 weight-percent of aromatic based upon isobutane and olefin (both fresh and recycled, but exclusive of nbutane) is present in the reaction zone. Between about 0.1 and 1.0 weight-percent is preferred. As the introduction of aromatic hydrocarbon into the reaction zone is begun, there is an increase in the octane number of the alkylate but also a slight decrease in yield thereof. As

larger amounts of aromatic hydrocarbon are used, the

' cent when using meta-xylene) the octane number ceases the octane number and is even more eliective since it to increase. Thereafter, no further improvement in octane number is obtained with additional amounts of aromatic hydrocarbon, but the yield continues to decrease. Obviously therefore, no more than 1.5 weightpercent of the aromatic hydrocarbon should be used, and

the economically desirable amount will be even less depending upon the particular aromatic hydrocarbon used.

A number of experiments were carried out relative to the present invention. In all of the alkylation experiments carried out, the procedure consisted of introducing the catalyst and the aromatic hydrocarbon (when used) into a 700 cc. stirred autoclave. The isobutane was then forced into the autoclave with nitrogen pressure, the stirrer started, and olefin introduced at the rate of 60 mL/hr. over a period of 2.5 hours. The stirring was continued for 10 minutes after all the olefin had been added. After settling, the liquid product was removed under its own pressure and collected in a Dry Ice trap. Isobutane was removed by stabilization and the alkylate distilled to secure a 400 F. E.P. gasoline, the octane number (CPR-R) of which was determined.

The first series of experiments, which are reported in Table I, shows that the mono-nuclear aromatic causes an increase in the octane number only when the aluminum chloride-ether catalyst is used. The aluminum chloride in dimethyl ether catalyst used in runs 1 and 2 was prepared by passing gaseous dimethyl ether into a Dry Icecooled flask containing aluminum chloride. Eventually a separate liquid phase was formed containing aluminum chloride in solution and suspension. The dimethyl ether introduction was discontinued when a catalyst composi tion of weight-percent aluminum chloride and 20 weight-percent dimethyl ether was reached. This corresponds with 1.4 mols of aluminum chloride per mol of dimethyl ether. In all runs reported herein, wherever an aluminum chloride-dimethyl ether catalyst was used, it was prepared in this manner. In runs 3 and 4 an aluminum chloride-diethyl ether catalyst was used which had been prepared by dissolving aluminum chloride in grams of diethyl ether which was contained in a Dry Icecooled flask. The aluminum chloride was added slowly, considerable heat being evolved, resulting in the evaporation of some of the diethyl ether. Aluminum chlorideether complex settled out as a solid and with further aluminum chloride addition, the entire mixture became solid. The complex was gradually warmed to room temperature and as it melted, additional aluminum chloride was added. The saturated solution, together with excess aluminum chloride, was heated to about F. and cooled to room temperature to insure that the 1:1 aluminum chloride-ether complex was completely saturated with an excess of aluminum chloride. In all, a total of 250 grams of aluminum chloride was added (corresponding with a molar ratio of aluminum chloride/diethyl ether of at least 1.4:1). The BF -ether-HF catalyst was made by adding 5 grams of HP to 10 ml. of an equimolar BF -ether solution. The BFg-HzO-HF catalyst used in runs 7 and 8 was prepared by saturating 48% hydrofluoric acid with 8P under 100 p.s.i.g. In runs 1 through 8 approximately 10 ml. of catalyst, 300

gms. of isobutane, and 90 gms. of butene-2 were used.

The Operating temperature was about 75 F. In runs No. 9 and a sulfuric acid catalyst of 97% concentration was employed with an equal volume of hydrocarbons (180 grns. of isobutane and 45 gms. of butene-2) at a 8 mine the eflect of various aromatic hydrocarbons on the yield and octane number of the alkylate produced. In this series of runs an aluminum chloride-dimethylether catalyst, prepared in the manner previously described,

temperature of 40 F. The results obtained are shown 5- was used to catalyze the reaction of isobutane with butenem Table I was follows: 2. The procedure, reaction conditions, amounts of cat- Table I alyst, isobutane and butene-2 were the same as used in runs No. 1 and 2 supra. The efiect of the use of various aromatic hydrocarbons 1s shown in Table III whlch Amount Yield, Percent Octane f H Run Catalyst Aro- Wt. Per- 400 N o. 10 0 No. matic, cent on F.E.P. CFR R percent olefin gasoline Table III 1 AlClg-dimethylether. none 210 95 89.0 400 F. E. P. gasoline AlCk-dimethylether. 0. 5 185 94 99. 2 Yield, AlCh-diethylethen--- none 190 97 88. 5 Run No. Aromatic Wt. A1Cl3-diethylether 1.0 160 95 99.0 Hydrocarbon percent on Percent of Octane 5-. BF -ether-IlFun none 182 85 90. l olefin total No.

BFi-ether-HF-. 0.5 180 83 90.6 alkylate CFR-R BFa-HzO-HF. none 181 95 85.7 BFa-HaO-HF- 0. 5 185 94 85. 9 H2SO4 none 176 96 94.7 211 98 89.9 H 804 l. 0 183 90 95- 7 141 85 99. 7 182 94 98. 8 175 93 99. 1 1 Weight percent concentration based on total of amount of isobutane 165 92 99.6 and butene2. In runs N o. 3 and 4, m-xylene was used and in all other 189 95 99.0 runs hcxamethylbenzene was the aromatic. 159 90 99.3 2 Percent based upon total liquid product. 180 94 97. 6 Hexaethylbenzene 192 98. 8 From a comparison of the runs it is evident that the aro- Butylated 11195719116 189 88 1 Recycled aromatic 198 95 96. 5 matic hydrocarbon 1s beneficial 1n substantlally improving the octane number of the alkylate only when it is used in conjunction with an aluminum chloride-ether catalyst.

A study was made wherein different olefins were employed in alkylating isobutane. In this study an aluminum chloride-dimethylether catalyst, prepared in the manner previously described, was used for the alkylation of isobutane with the various olefins while using reaction conditions and amounts of catalyst, isobutane, and olefin as employed in runs No. 1 and 2 supra. Runs were made with and without added aromatic hydrocarbons. The results obtained are shown in Table II which follows:

Table II 400 F. E. P. gasoline Amount Aromatic, percent refinery butenes refinery butcnes L 1 Weight percent concentration based on total amount of isobutane and olefin. m-Xylene was the aromatic used, except in runs N o. 16 and 22 wherein hexaethylbenzene was used.

2 Mixed butanes-butenes from catalytic cracking consisting of: propane 0.8%; isobutane 36.5%; n-butane 9.3%; butenel 11.3%; isobutene 24.5%; butene-2 17.6%. Experiments used 275 gm. isobutane, 120 gm. refinery butenes stream, and 15 ml. catalyst.

It can be seen from the above table that the introduced aromatic causes an increase in the octane number of the alkylate only when the reacting olefins are butene-2, isobutene, and propene. The greatest improvement was obtained with butene-2. When the reacting olefin was butene-l, the use of the aromatic hydrocarbon resulted in a decrease in the octane number of the alkylate; and when the reacting olefin was ethene the use of the aromatic hydrocarbon stopped the alkylation reaction. When the source of olefin was the mixed butanes-butenes stream from catalytic cracking, introduction of the aromatic hydrocarbon caused a very substantial increase in the octane number of the alkylate.

An additional series of runs was carried out to deter- Used; in amount of 0.25 wt. percent based on isobutane and olefins, 1.0 wt. percent in all other runs.

2 Containing approximately 1.5 butyl groups per molecule.

3 m-Xylene and alkylated forms thereof recovered from product and recycled.

From the above table it can be seen that the mono-nuclear aromatic hydrocarbons are beneficial for the purpose of increasing the octane number of the alkylate produced. Although there is some reduction in the yield, it appears that when the polyalkylated benzenes are employed this yield reduction is minimized. Thus compounds such as m-xylene, hexaethylbenzene and similar polyalkylbenzenes cause an increase in the octane number of the alkylate of about 10 units and reduce the yield by only about 10%. When polynuclear aromatics are used, the catalyst becomes deactivated by a visible tarry material.

A further series of runs was carried out wherein the amount of aromatic hydrocarbon introduced into the alkylation zone was varied. In this series of runs, which is shown in Table IV, an aluminum chloride-dimethylether catalyst, prepared in the manner previously described, was used to catalyze the reaction between isobutane and butene-2. The amount of catalyst and hydrocarbons as well as the procedure and reaction conditions were the same as those previously reported for runs No. l and 2. The aromatic hydrocarbon employed was hexaethylbenzene. It was used in amounts ranging between 0.28 and 2.24 weight percent based upon the total isobutane and butene-2 introduced into the reaction zone. The results obtained are shown in Table IV which follows:

Table IV Concentra- Liquid Octane Run N 0. tion of yield, N o

Aromatic, wt. percent FR-R percent on olefin The results obtained and shown in Table IV are plotted graphically in the attached Figure l which form a part of this specification. It is readily apparent from this figure that a maximum increase in octane number is reached when about 0.3 to 0.4 Weight percent of hexa-, ethylbenzene (based upon isobutane and olefin) is introduced into the reaction zone. The addition of further amounts of the aromatic hydrocarbon does not increase the octane number of the alkylate produced but does decrease the yield of liquid alkylate substantially. Consequently, with this particular aromatic hydrocarbon no more than about 0.4 weight percent based on isobutane and olefin should be employed. In considering both the yield and octane number, it is preferable to employ somewhat less than 0.3 weight percent of this aromatic hydrocarbon.

Figure 2 illustrates a preferred embodiment of the process of our invention in a diagrammatic form. It describes a process for alkylating isobutane with butenes. Numerous valves, pumps, etc. have been omitted for purpose of clarity.

Referring to Figure 2, a mixed butanes-butenes stream recovered from the products of the catalytic cracking of gas oils is passed 'under a pressure of 100 to 500 p.s.i.g., e.g., 250 p.s.i.g. from source 11 by way of line 12 into vessel 13 which contains an aqueous caustic solution for removing mercaptans and hydrogen sulfide. A typical butanes-butenes stream from catalytic cracking will have from 30 to 40% isobutane, 10% n-butane, 25% isobutene, 10% butene-l, and 20% butene-Z. The caustic washed hydrocarbons are removed from vessel 13 and passed through line 14 where they meet recycled isobutane in an amount such that the isobutane/olefin weight ratio is about 4:1. and butenes is then passed by way of line 14 into water settler 16 from which water is removed and discarded by way of line17. Although not shown herein, the hydrocarbons usually are dried by passing through a dehydrator such as employs bauxite, etc. The hydrocarbon stream is removed from settler 16 and. passed by way of line 18 to chiller 21. mXylene is introduced from source 19 by way of line 20 into line 18 in an amount such that its concentration in the alkylation reactor is about 0.5% by weight based upon isobutane and olefins present in the hydrocarbon stream within the reactor. The hydrocarbons which have been chilled in chiller 21 are then passed by way of line 22 into alkylation reactor 23. The alkylation reactor may be any of a number of varied types such as the impeller type reactor system as is diagrammatically indicated herein, the jet type, timetank system or others. It is provided with a vbayonette tube cooling bundle 2.4 through which refrigerant flows to remove the heat of reaction liberated in the process.

In alkylation reactor 23, the liquid mixture of butanes and butenes at a temperature of about 70 F. is intimately contacted with an aluminum chloride-dimethyl ether cata lyst containing about 1.5 mols of aluminum chloride per mol of dimethyl ether. The hydrocarbon/ acid volumetric ratio is about 75:1. is about 200:1. A contact time of about 1 hour is used.

From alkylation reactor 23, a mixed stream of hydrocarbons and catalyst is withdrawn and is passed by way of line 26 into catalyst settler 27. The settled catalyst is removed and recycled by way of line 28 (with added fresh catalyst when necessary) and thus returned to reactor 23. The hydrocarbon layer from settler 27, which consists of alkylate, excess isobutane, and the unreacted butanes and butenes, is passed by way of line 29 into vessel 31 which contains an aqueous caustic solution for The isobutane fortified mixture of butanes' The internal isobutane/ olefin ratio removing small amounts of contaminants. The caustic V washed hydrocarbons are then removed from vessel 31 and passed by way of line 32 into the fractionation section of the alkylation plant.

The caustic washed product is passed by way of line 32 into deisobutanizer 33 from which an overhead stream of recycle isobutane is taken and passed by way of line 34 into line 14 for the purpose of fortifying the butanesbutenes stream with respect to isobutane. Outside isobutane may be introduced from source 36 by way of valved line 37 into line 34 when necessary. A slip stream portion of the isobutane recycle stream is removed from line 34 and passed by way of line 38 into depropanizer 8 39 from which an overhead stream of propane is removed by way of line 41 and sent to storage means not shown, and a stream of purified isobutane is removed by way of line 42 and returned to isobutane recycle line 34. A bottoms stream is removed from deisobutanizer 33 and passed by way of line 43 into debutanizer 44 from which an overhead stream of n-butane is removed by way of line 45 and sent to storage means not shown. A bottoms stream from fractionator 44 is removed and passed by way of line 46 into fractionator 47. An overhead stream of gasoline boiling range alkylate having an end point of about 360 F. is removed overhead from fractionator 47 by way of line 48 and sent to storage means not shown. This alkylate will have an octane number between about 94 and 98 CFRR and is an excellent stock for blending to form gasolines of very high octane number. A bottoms fraction consisting of the high boiling components of alkylate is removed from fractionator 47 by way of line 49 and sent to storage means not shown.

While the invention has been described with reference to certain specific examples, the invention is not to be considered as limited thereto but includes within its scope such modifications and variations as would occur to one skilled in this art.

What is claimed is:

1. The process of alkylating isoparatfins with olefins which comprises introducing isobutane and at least one olefin selected from the group consisting of propene, butene-Z, and isobutene into a reaction zone, therein intirnately contacting in the liquid phase the isobutane and olefin with an aluminum chloride-ether catalyst under alkylation reaction conditions and in the presence of a mono-nuclear aromatic hydrocarbon in the amount of between about .001 and 1.5 weight-percent based upon isobutane and olefin present in the reaction zone whereby alkylation products are formed, said aluminum chlorideether catalyst containing more than one but less than two mols of aluminum chloride per mol of ether and being formed of a solution of aluminum chloride in at least one ether selected from the group consisting of di methyl ether and diethyl ether, removing the alkylation products from said reaction zone, and recovering a gasoline boiling range alkylate from the alkylation products.

2. The process of claim 1 wherein said mono-nuclear aromatic hydrocarbon is a polyalkylbenzene.

3. The process of claim 1 wherein said mono-nuclear aromatic hydrocarbon is employed in an amount between about 0.1 and 1.0 weight-percent based upon isobutane and olefin introduced into said reaction zone.

4. The process of claim 1 wherein said mono-nuclear aromatic hydrocarbon is introduced into said reaction zone together with the isobutane.

5. An isobutane alkylation process which comprises introducing isobutane and at least one olefin selected from the group consisting of propene, butene-Z, and isobutene into a reaction zone, said isobutane and olefin being introduced in a ratio of at least three mols of isobutane per mol of olefin, intimately contacting in said reaction zone the isobutane and olefin in the liquid phase under alkylation reaction conditions with an aluminum chloride-ether catalyst in the presence of a polyalkylbenzene in the amount of between about 0.1 and 1.0 weightpercent based upon isobutane and olefin present in the reaction zone and thereby forming alkylation products of the isobutane and olefin, said aluminum chloride-ether catalyst containing more than one but less than two mols of aluminum chloride per mol of ether and being formed of an equimolar aluminum chloride-ether liquid complex which is saturated with aluminum chloride, said ether being at least one ether selected from the group consisting of dimethyl ether and diethyl ether and said alkylation conditions comprising a temperature between about 50 and 100 F. and a volumetric ratio of hydro carbons to catalyst of between about 10 to 100:1, remov 9 1O ing the alkylation products from said reaction zone, and References Cited in the file of this patent recovering a gasoline boiling range alkylate from said UNITED STATES PATENTS alkylaticn products having an octane number higher than 2,368,653 Francis Feb. 6, 1945 232d be produced m the absence of sand polyalkylben 5 2,405,516 Pines Aug 6, 1946 6- Th f 1 5 h 1 1b 2,415,733 DOuville Feb. 11, 1947 6 Process 0 c 31m W ereln Sal P Yalky en 2,477,290 D omte July 26 1949 zene is xylene. 

1. THE PROCESS OF ALKYLATING ISOPARAFFINS WITH OLEFINS WHICH COMPRISES INTRODUCING ISOBUTANE AND AT LEAST ONE OLEFIN SELECTED FROM THE GROUP CONSISTING OF PROPENE, BUTENE-2, AND ISOBUTENE INTO A REACTION ZONE, THEREIN INTIMATELY CONTACTING IN THE LIQUID PHASE THE ISOBUTANE AND OLEFIN WITH AN ALUMINUM CHLORIDE-ETHER CATALYST UNDER ALKYLATION REACTION CONDITIONS AND IN THE PRESENCE OF A MONO-NUCLEAR AROMATIC HYDROCARBON IN THE AMOUNT OF BETWEEN ABOUT .001 AND 1.5 WEIGHT-PERCENT BASED UPON ISOBUTANE AND OLEFIN PRESENT IN THE REACTION ZONE WHEREBY ALKYLATION PRODUCTS ARE FORMED, SAID ALUMINUM CHLORIDE ETHER CATALYST CONTAINING MORE THAN ONE BUT LESS THAN TWO MOLS OF ALUMINUM CHLORIDE PER MOL OF ETHER AND BEING FORMED OF A SOLUTION OF ALUMINUM CHLORIDE IN AT LEAST ONE ETHER SELECTED FROM THE GROUP CONSISTING OF DIMETHYL ETHER AND DIETHYL ETHER, REMOVING THE ALKYLATION PRODUCTS FROM SAID REACTION ZONE, AND RECOVERING A GASOLINE BOILING RANGE ALKYLATE FROM THE ALKYLATION PRODUCTS. 